The present invention relates to fossil fuel burning furnaces, more particularly to a furnace which is utilized to boil water and heat steam for the production of electricity.
The present known means of achieving an optimum fuel oxygen mixture in these furnaces is to force large volumes of air over a fluidized or moving bed of coal or other fuel. The oxidation of these fuels in the presence of air produces flue gases that are classified as pollutants, such as nitrous oxides and other gases. These pollutants are known to contribute to the acid rain phenomenon and greenhouse effect, the primary cause of global warming. New technologies are being developed to control the emission of these gases. To date the known methods of emission control have proven to be costly and inefficient. Some methods use a chemical feedstock injected into furnace or effluent stream. Others have developed a procedure termed less excess air, and others have found benefit in producing a higher temperature flame. The best results known to date approach 90% reduction of SO.sub.2 and/or NO.sub.x. These technologies require more than 15% of the power generated at the facility, impairing rather than enhancing furnace efficiency. The novelty of this invention far exceeds its ability to limit nitrous oxide emissions. There is no known prior art in these areas which include the production and use of liquid nitrogen to cool steam, resulting in higher turbine efficiency and eliminating the need of cooling towers. The nitrogen is a by product of an air fractional distillation system which produces liquid oxygen used as a source for oxygen enrichment of the furnace.
The most pertinent prior art is U.S. Pat. No. 5,052,310 Goff et al. The proper areas of classification of the present invention are believed to be U.S. Pat. No. 110.